Various foodstuffs, liquids, and other substances can be sterilely packaged in pouch-type flexible containers made from webs of flexible film, sheet stock, or like material that is sealed together along the peripheral edges. There are a number of advantages to these pouch-type flexible containers, including low weight, durability, and low cost fabrication.
Various medical solutions are sterilely packaged in pouch-type flexible containers. The medical solutions can be pharmaceutical, flushes, nutrition, irrigating, respiratory therapy agents, dialysis, blood, blood products, plasma derivatives, plasma expanders, blood substitutes, anti-coagulants, blood preservatives, and the like. Such solutions can be delivered to a patient through an administration tubing set connected with the flexible container. Other medical solutions include enterals, anesthesia inhalants, veterinarian, media, and the like. The container may include one or more access tubes or fittings through which the liquid is pumped to fill initially the container during manufacture of the package and to which the administration set and
The use of bar coding to identify the contents of a container is widespread in the medical industry. For example, bar code identification systems allow a hospital to track electronically its inventory of pharmaceutical products, and the subsequent billing to the patient for the use thereof. Bar codes are also used in automated agent compounding systems to mix properly the correct and proper amounts of medical and therapeutic agents. More important, bar codes also allow hospitals to monitor its medications or other therapeutic fluids that are targeted for infusion into its patients by marking same with fixed information such as product code names or numbers.
Historically, a two-color system was implemented in bar coding systems. That is, a typical bar code consisted of black lines on a white background. When a bar code reader would read the bar code, the black lines would absorb the reader's laser light while the white spaces would reflect the reader's laser light back to the reader where the reflected information was translated into its corresponding analog counterpart. This two-color system naturally led to the development of a two-step process for printing the bar code.
First, the container was passed through a printing machine that applied a reflective (generally white) background field for the bar code. Next, the container was passed through a second printing machine that applied the dark, light-absorbing lines of the bar code over the top of the background field. One common printing method was the hot-stamping (die-cast) system.
In a hot-stamping system, a metal die is engraved in the desired image or bar code, heated to a pre-determined temperature, and applied under pressure to the substrate in order to transfer the image or bar code from the hot-stamp foil. The foil acts as the pigment (ink) carrier and is fed between the hot-stamp die and the substrate. One problem is that the die has sharp edges that oftentimes damage the flexible substrates heretofore mentioned, thus increasing the scrap rate. Still yet another problem is that the hot-stamp die is costly to produce, taking several hours, or even days, to manufacture. Accordingly, a hot-stamping system is unsuitable for printing images representative of variable information such as lot numbers, batch numbers, expiration dates or any other data that changes in a fixed time period, such as by the minute, hour, or day.
Consequently, the hot-stamping system can be used to print feasibly only fixed information such as a product's name, manufacturer, and the like. One method of overcoming this deficiency is to print labels and apply them to the product. Naturally, this increases costs and decreases production rates, as well as opens the possibility for the label(s) to fall off of the product.
Several other problems exist with the hot-stamping system as it relates to the readability of the bar codes on flexible, transparent containers such as those commonly used in the medical industry. The first problem with the readability of images printed by the hot-stamping system is that the transparent (light-absorbing) nature of the containers in such systems requires that a solid (light-reflecting) background block be printed on the container before the dark (light-absorbing) lines of the bar code can be printed thereon. Not only is there the increased cost associated with two printing passes to achieve the two colors, but it is also fundamentally difficult to print a solid background block using the hot-stamping method because air pockets commonly form in the ink, which cause voids in the block, resulting in an unreadable bar code. Additionally, because the background block naturally requires more pigment or ink than the contrasting bars, there is an increased risk for pigment extractives and leachables to exist in the container's solution.
A second problem is that because the hot-stamping system uses variable heat, variable pressure, and a fixed dwell time to transfer images or bar codes onto the substrate, there is a problem of the ink bleeding or growing too thick, which causes an unreadable bar code or poor edge definition of the bar code symbology. To correct this problem, the dies have to be redesigned, re-machined, or re-engraved at a reduced size so that when applied, the correct bar code size is achieved. Alternatively, the size of the bar code symbology, including bar spacing, could be increased if space limitations on the substrate so allowed. Both solutions, however, increase costs and decrease productivity. A third problem is that the inks in a hot-stamping system are designed to adhere to the underlying substrate, and not each other, further contributing to an unreadable bar code and mandating the development of inks that adhere to each other. Fourth, hot-stamping typically yields a bar code with a “D” or “F” American National Standards Institute (ANSI) scale read (with “A” being the highest resolved image). See e.g, American National Standard for Information Systems—Bar Code Print Quality Guidelines, by The American National Standards Institute, © 1990 by Information Technology Industry Council, and which is incorporated by reference as though set forth herein.
At least one attempt has been made to reduce the problems associated with a two-color, hot-stamping system, and is found in PCT patent application number PCT/US99/05614, bearing International Publication Number WO 99/49408, which is incorporated herein by reference as though fully set forth herein. The '408 application discloses a container bearing a negative image bar code generated using the above-described hot-stamping system (page 8, lines 22–24). The bar code is a negative image in that the light-reflecting segments of the underlying substrate correspond to the background spaces (generally white) of a traditional bar code, and the light-absorbing segments of the underlying substrate correspond to the light-absorbing dark segments (generally black) of a traditional bar code.
Even prior thereto, the ability to print a negative bar code image had been known in the art as evidenced in the publication Barcodes and Other Automatic Identification Systems, by Robert D. LaMoreaux at page 176, © 1995 by Pira International, which is incorporated herein by reference as though fully set forth herein. Notwithstanding the advantages of a one-color system, the remaining aforementioned problems with the hot-stamping system still exist, including the inability to print fixed and variable information in a single printing pass.
Unlike the hot-stamping system, the thermal transfer printing system uses a low level of heat that transfers images (such as a bar code) from a printing head under light contact with the substrate. Because the bar code is not printed under pressure, there is a superior bar code symbology edge definition. That is, thermal transfer printing generally yields bar codes with an “A” or “B” ANSI scale read. Furthermore, the present inventors found that when an “A” quality code is printed using the thermal transfer system, the same code produces a “C” quality read through a 10 mil high-density polyethylene overpouch, the overpouch being well-known in the medical art.
Another benefit of the thermal transfer printing system is that because the print head contains no sharp edges like the hot-stamp die, the print head does not damage the flexible substrate, thus reducing the scrap rate. Another benefit is that the thermal transfer printing system uses less pigment or ink that the hot-stamping system, resulting in a lower risk of leachables or extractables in the container's solution. Still another benefit is that the thermal transfer printing head yields a higher degree of flexibility than the hot-stamp die because the image information can be easily changed in a matter of minutes at an input terminal, as opposed to waiting hours, or even days, for a hot-stamp die to be redesigned, re-machined, or even re-created. There are a number of these thermal transfer systems commercially available from different manufacturers such as SmartDate® (MARKEM) and Jaguar J27i4 (Norwood Marking Systems).
Still yet another benefit of the thermal transfer printing system over the hot-stamping system is the ability to print smaller bar codes that will be accurately read. For example, the thermal transfer printing system requires on average approximately one-third to two-thirds of the length required for the hot-stamping system to print a code of a comparable symbol grade, depending on the substrate. In short, the thermal transfer printing system requires less space and provides superior bar code edge definition over the hot-stamping system. These advantages allow one to print fixed and variable information, including the label copy information, on pharmaceutical and medical agents, on either side, or both sides, of a container. Conversely, the size and resolution limitations of the hot-stamping method force one to print fixed information on one side of the container and variable information on the other side. These limitations add the manipulation of turning the container over and running a second printing pass, which in turn, increases costs and decreases productivity. Accordingly, the thermal transfer printing system affords improved cost efficiency, time efficiency, and bar code image resolution over the hot-stamping system. Notwithstanding, there still exists the problem of printing in a single pass a high resolution, one-color bar code that contains both fixed information and variable information.
The present invention is provided to solve these and other problems.